FBI Examining Malaysia Airlines Pilot's Flight Simulator

The FBI is examining the home made flight simulator that belonged to the captain of the missing Malaysia Airlines flight and a key question will be trying to determine what the captain deleted and whether it's key to the investigation.

The simulator's hard drive and data were taken from the home of Capt. Zaharie Ahmad Shah this week as part of investigators' efforts to determine whether the crew of the plane could have been complicit in whatever happened to the flight and the 239 people on board. Authorities are baffled about the plane's disappearance, but have determined that it was a "deliberate act."

An initial review of the simulator, which the captain had boasted on YouTube of building himself, found nothing suspicious and no indications of plotting the plane's disappearance, but the FBI will scour the hard drive.

The FBI's role in examining the simulator was confirmed to ABC News by a U.S. official hours after Malaysian officials told a news conference that the veteran pilot had deleted files from the simulator and investigators were trying to determine what had been erased.

Some of the files were deleted on Feb. 3, Malaysian Police Chief Khalid Abu said at a news conference today. The family of the pilot is cooperating with the investigation, officials said.

After the simulator was confiscated earlier this week, ABC News aviation expert John Nance said that officials would be looking through the simulator data to see if the captain practiced maneuvers similar to those done by MH370 after it disappeared from radar.

They will also look for "Any indication that the simulator could practice anything untoward like practicing landing on small islands in the ocean," Nance said.

Despite the focus on the flight simulator, Malaysian officials said they are not ruling out any possibilities.

"I would like to take this opportunity to state that the passengers, the pilot and the crew remain innocent until proven otherwise," Acting Transport Minister Hishammuddin Hussein said today.

Today's daily news conference was marked by angry relatives of passengers who shouted insults at Malaysian authorities and held up a banner in protest. A chaotic scene ensued in the Sama Sama Hotel in Kuala Lumpur as police tried to escort the relatives out of the area. The families were first escorted into a holding room, but when police emerged from the room and tried to move them out of the area pushing and shouting erupted as camera crews tried to get near the families.

The families, devastated by the plane's disappearance, have become frustrated by the lack of information.

"It's really too much. I don't know why it is taking so long for so many people to find the plane. It's 12 days," Subaramaniam Gurusamy, 60, said in an interview from his home on the outskirts of Kuala Lumpur. His son, Pushpanathan Subramaniam, 34, was on the flight heading to Beijing for a work trip.

"He's the one son I have," Subaramaniam said.

As the frustrations mount, the plane's path and final position remain a mystery. Officials today rejected suggestions that islanders in the Maldives, an island chain in the southern Indian Ocean, saw the jetliner flying low in the sky.